JPS6054812B2 - riveting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a riveting method in which the rivet is heated by resistance heating and the head of the rivet tip is simultaneously formed.

Conventionally, in this type of riveting method, as shown in FIG. 1 of the accompanying drawings, materials to be riveted 2 having rivet holes 1 are placed on top of each other, and a tip portion 3a) is placed in the rivet hole 1 of the materials 2 that are stacked on top of each other. Insert the rivet 3 consisting of a shaft portion having a shaft portion 3b and a head portion 3c, and
and the head 3c are held between the electrodes 4 and 5, heated by a power supply (not shown), and simultaneously applied pressure to both electrodes 4 and 5, thereby forming a rivet. The rivet 3 was tightly filled into the hole 1 and the head portion of the tip portion 3a was plastically formed.

However, in the riveting method performed in this way, as shown in FIG. The back side of part 3c and the material to be riveted 2
A shunt flow 8 flowing into the material to be riveted 2 through the contact portion 7 with
Because the main current 6 is reduced by dividing into two parts, and in addition to this, the heat of the rivet 3 heated and heated by the main current 6 is thermally diffused to the material 2 to be riveted. The tip portion 3a is heated and temperature rises faster than the portion 3b near the rivet head, and as a result, due to the pressure applied by both electrodes 4 and 5, the tip portion 3a of the rivet 3 starts plastic deformation, and the rivet The shaft portion of the rivet 3, particularly the portion 3b near the rivet head, does not undergo plastic deformation due to insufficient temperature rise, and therefore, the entire shaft portion of the rivet does not completely fill and adhere to the rivet hole 1, and the tip portion 3a As shown in FIG. 3, the head is formed.

When the head is formed in this way, a contact portion 9 is also generated between the formed head and the material to be riveted 2, and from this contact portion 9, the current flowing between the electrodes 4 and 5 is also transmitted. Since the shunt occurs, even if the current is continued thereafter, the current will not concentrate on the rivet 3, and therefore the temperature of the portion 3b near the head of the rivet 3 will not rise much. Furthermore, rivet 3
Since the material to be riveted 2 is sandwiched between the contact portions 7 and 9 between the head portion 3c and the molded head portion of the tip portion 3a and the material to be riveted, the electrodes 4 and 5 are Rivet 3
The forming pressure applied to the rivet material 2 is dispersed to the rivet material 2, and does not act on the shaft portion of the rivet 3, especially the portion 3b near the head. In this way, the portion 3b near the head cannot be plastically deformed due to insufficient temperature rise and insufficient pressure, and therefore,
The shaft portion of the rivet 3 will not be able to completely fill and fit into the rivet hole 1. In particular, when the rivet diameter and the length of the rivet shaft are large, this type of drawback is likely to occur. In this way, the rivet shaft part is connected to the rivet hole 1.
In the case of riveted joints that are not tightly filled, if these riveted joints are used in construction areas that are subjected to repeated loads or in areas where strength is important, the applied strength will decrease,
Therefore, there was a drawback that it could not be applied.

An object of the present invention is to obtain a riveting method that eliminates such conventional drawbacks, and includes:
In order to achieve this purpose, the cross-sectional area is small and the height is set between the back surface of the rivet head and the material to be riveted at the same time or after the rivet shaft is sufficiently tightly packed into the rivet hole. This is characterized in that a spacer is provided at a height such that the back surface of the head and the material to be riveted come into contact with each other, and electrical heating and pressing are performed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings showing one embodiment thereof.

In FIG. 4, reference numeral 10 denotes a spacer, which is a ring-shaped spacer inserted into the rivet 3 to maintain a gap between the back surface of the head 3c of the rivet 3 and the material 2 to be riveted. It is a spacer made of conductive metal, and when the rivet 3 is heated by electricity while being sandwiched between the electrodes 4 and 5, the heating current flows from the back surface of the head 3c to the material to be riveted due to its small cross-sectional area. The height of the spacer 10 is suppressed, and when pressurized, the rivet hole 1 is tightly filled with the shaft portion of the rivet 3, especially the portion 3b near the head, due to its plastic deformation. Therefore, the back surface of the head 3c is prevented from coming into contact with the material to be riveted.

Further, in the above embodiment, the spacer 10 was provided as a spacer separately from the rivet 3 or the material to be riveted 2, but instead of this spacer, the spacer 10 was provided as a spacer for the head of the rivet 3''. 3c may be provided with a protruding surface 20 on the back surface, as shown in FIG. 5, and its function is exactly the same as that of the spacer 10 in FIG. ,
The spacer 10 is attached to the rivet 3, or if the rivet 3'' is provided with a protruding surface 20, the rivet is inserted into the rivet hole 1, and then the electrode 4,
When the tip part 3a and the head part 3c of the rivet 3 are held between the rivet parts 5 and 5, and the electrodes 4 and 5 are heated with electricity and pressure is applied, the rivet material 2 is moved from the back side of the head part 3c of the rivet 3 to the material 2 to be riveted. The shunt flow is suppressed, and most of the current applied to the electrodes 4 and 5 flows through the shaft portion of the rivet 3.

Therefore, heating of the portion 3b near the head portion 3b is promoted and the temperature increases similarly to other portions of the shaft portion, and the spacer portion, that is, the spacer 10 or the protruding surface 20 is plastically deformed even when pressurized. Along with this, the rivet head vicinity portion 3b due to the rivet forming pressure is removed until the gap formed between the back surface of the head 3c of the rivet 3, 3'' and the material 2 to be riveted disappears.
This stress concentration is maintained for a long period of time, and therefore, the rivet shaft portion, particularly the portion 3b near the head portion 3b, is sufficiently tightly filled into the rivet hole 1. The invention is carried out in this way, so that the rivet can be fully and tightly packed in the rivet hole over the entire surface, so that a sufficient rivet joint with very good working strength can be produced with low current and in a short time. Therefore, it has the effect of being able to be safely applied to locations that are subject to repeated loads or locations that are important in terms of strength.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of the conventional riveting method, FIGS. 2 and 3 are explanatory diagrams showing its drawbacks, FIG. 4 is an explanatory diagram showing an embodiment of the present invention, and FIG. 5 is an explanatory diagram of the conventional riveting method. FIG. 3 is an explanatory diagram showing another embodiment.

1... Rivet hole, 2... Material to be riveted, 3... Rivet, 3a... Tip part, 3b... Near head Part, 3c...
Head, 4, 5... Electrode, 6... Main current, 7, 9... Contact part, 8... Branch current,
10...Spacer portion (spacer), 20...Protrusion surface.

Claims (1)

[Claims] 1. In a riveting method in which the head and tip of a rivet are sandwiched between a pair of electrodes, heated with electricity, and pressed, the gap between the back surface of the head of the rivet and the material to be riveted is In addition, a spacer part having a small cross-sectional area and a height such that the shaft part of the rivet is sufficiently tightly packed into the rivet hole or the back surface of the head part and the material to be riveted come into contact after that is provided. A riveting method characterized in that the riveting method is performed by riveting. 2. The riveting method according to claim 1, wherein the spacer is a ring-shaped conductive metal spacer into which the rivet shaft is inserted. 3. The riveting method according to claim 1, wherein the spacer is a ring-shaped protruding surface provided integrally with the rivet on the back surface of the rivet head.